There has been known a fuel pump that sucks fuel into a gear accommodation chamber and then discharges the fuel. A fuel pump disclosed in Patent Document 1 includes an outer gear having a plurality of internal teeth, an inner gear that has a plurality of external teeth and eccentrically engages with the outer gear, and a pump housing that defines a gear accommodation chamber in which the outer gear and the inner gear are rotatably accommodated. In the fuel pump, the outer gear and the inner gear rotate while expanding and reducing a volume of each of a plurality of pump chambers formed between the gears, thereby fuel is sucked into the gear accommodation chamber and then discharged.
In detail, the pump housing disclosed in the Patent Document 1 includes a pair of sliding surfaces that clamps the outer gear and the inner gear from both sides so that the gears slide on the surfaces, a suction port part that sucks the fuel from the outside to the inside of the gear accommodation chamber, and a discharge port part that discharges the fuel from the inside to the outside of the gear accommodation chamber.
Each of the suction port part and the discharge port part has two opening bores that are opened to a portion, which is opposed to a pump chamber, of the sliding surface from the outside of the gear accommodation chamber, and one rib disposed between the two opening bores.